20315217 has 16 divisors (see below), whose sum is σ = 29348928. Its totient is φ = 12425280.

The previous prime is 20315203. The next prime is 20315219. The reversal of 20315217 is 71251302.

It is not a de Polignac number, because 20315217 - 2⁴ = 20315201 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20315193 and 20315202.

It is not an unprimeable number, because it can be changed into a prime (20315219) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5242 + ... + 8252.

It is an arithmetic number, because the mean of its divisors is an integer number (1834308).

Almost surely, 2^20315217 is an apocalyptic number.

It is an amenable number.

20315217 is a deficient number, since it is larger than the sum of its proper divisors (9033711).

20315217 is a wasteful number, since it uses less digits than its factorization.

20315217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3200.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 20315217 is about 4507.2405083377. The cubic root of 20315217 is about 272.8603856156.

Adding to 20315217 its reverse (71251302), we get a palindrome (91566519).

The spelling of 20315217 in words is "twenty million, three hundred fifteen thousand, two hundred seventeen".